JPS5824627B2 - Fuel control device for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel control device for an internal combustion engine that adjusts the amount of fuel according to the amount of intake air. It is related to.

In this type of fuel control device, when considering engine operability, emission measures, and fuel economy, it is possible to measure the amount of fuel according to the intake air amount of the engine and simultaneously supply the amount of fuel to each cylinder. It needs to be as uniform as possible.

Therefore, various means have been used in the past.

For example, a fuel injection nozzle that supplies fuel by making the flow rate characteristics as uniform as possible, or an independent fuel metering section for each cylinder, and the fuel metered by this fuel metering section is supplied to each cylinder. It has been proposed that fuel is injected from a fuel injection nozzle provided correspondingly.

However, in the case of the former, it is difficult to manufacture nozzles with exactly the same characteristics using current manufacturing technology, and it is necessary to select and use nozzles with similar characteristics from among Mr. It has the disadvantage of being complicated.

In the latter case, each fuel metering section must be machined as identically as possible depending on the cylinder, and the amount of waste will be small, so the machining accuracy must be increased, which makes it expensive. It has the disadvantage of becoming.

The present invention is an attempt to solve the above-mentioned drawbacks.The present invention is aimed at solving the above-mentioned drawbacks.The present invention measures the amount of fuel in accordance with the amount of intake air using a single twisted part adjusting slit, and directs the adjusted amount of fuel to the injection nozzle of each cylinder. By equally distributing the fuel to the cylinders using a distributor that is connected to the nozzle C and is unaffected by some degree of non-uniformity, the fuel metering device can be simplified and fuel can be supplied at low cost and with high accuracy. The purpose of this invention is to provide a fuel control device that can perform the following steps.

1, an internal combustion engine 1 is a well-known spark ignition type engine, and air is supplied from an air filter 2 through an intake pipe 3. In FIG.

The intake pipe 3 is provided with a throttle valve 4 that is connected to an accelerator pedal (not shown) and is opened and closed at will.
An air measuring section 5 for measuring the amount of air taken into the engine 1 is provided upstream of the throttle valve 4.

This air measuring section 5 includes a sensing valve 6 provided in the intake pipe 3.
, a return spring 1, and the sensing valve 6 rotates integrally with the fuel metering shaft 8 against the drag force of the return spring 7 in accordance with the amount of intake air passing through the metering section 5.

The pressure reactor 9 is for maintaining the pressure difference between the upper and downstream parts of the sensing valve 6 at a predetermined value, and is connected to the casing 10 and the diaphragm 1.
1 form two chambers 12, 13, and the diaphragm 11 is connected to the sensing valve 6 by a connecting rod 14.

The chamber 12 communicates with a port 15 provided downstream of the sensing valve 6 by a conduit, and the chamber 13 communicates with the upstream side of the sensing valve 6.

In FIG. 2 showing the fuel system, 16 indicates a fuel metering device, whose housings 17 and 18 are connected with a metal diaphragm 19 sandwiched between them, and these are integrally attached to the intake pipe 3. There is.

In addition, a bearing 20 is installed in the housing 17, 18, and this bearing 20 has a fuel metering slit 21 whose area is controlled in the circumferential direction according to the amount of intake air, and a fuel metering slit 21 for inflowing fuel. A population of 22 is set.

A fuel metering shaft 8 is rotatably supported by this bearing 20, and a fuel metering surface 23 is formed on the fuel metering shaft 8 at a portion corresponding to the fuel metering slit 21. An annular groove 24 is formed in a portion corresponding to the fuel population 22.

Further, a metal diaphragm 1 is provided in the housings 17 and 18.
9 are formed into chambers 25 and 26 separated by the upper chamber 2.
A fuel pipe 21, which serves as a valve seat, protrudes within 5, and a coil spring 28 is installed so as to press against a metal diaphragm 19, which serves as a valve body, thereby forming a constant differential pressure valve V.

The upper chamber 25 of this constant differential pressure valve V1 communicates with the fuel metering slit 21 via a fuel passage, and the lower chamber 26 communicates with the fuel port 22 via a fuel passage. The fuel pressure difference before and after the fuel metering slit 21 is controlled to be kept constant.

Fuel tank 30, fuel pump 31 for pumping fuel
, the pressure regulator 32 and the fuel return pipe 33 constitute a fuel supply source that supplies fuel at a constant pressure and is connected via a conduit 34 to the lower chamber 26 of the fuel metering device 16 .

The distributor 35 has a fuel inlet 36 connected to the fuel pipe 27 of the fuel metering device 16, a fuel return 38 connected to the fuel tank 30 via a pressure regulator 37 for returning excess fuel, and a fuel supply source 36 connected to the fuel pipe 27 of the fuel metering device 16. Pressure population 39 connected to
, and fuel outlets 40a to 40d, and fuel is supplied from these fuel outlets to fuel injection nozzles N that open into the intake pipes of each cylinder of the engine 1 via conduits.

In FIGS. 3 and 4 showing the structure of this distributor 35,
1st, 2nd, 3rd...Usings 4L42゜43 sandwich metal diaphragm 44.45 and eight bolts 46
are joined together.

This distributor 35 is exemplified as one for a four-cylinder engine, and the first and second housings 41 and 42 each have four chambers 47 and 48 partitioned by a metal diaphragm 44, respectively.

Further, the second and third housings 42 and 43 have chambers 49 and 50 partitioned by metal diaphragms 45, respectively.
are formed in four pieces each.

Furthermore, one chamber 51 is formed in the center by the second housing 42 and the metal diaphragm 45.

Each chamber 47 communicates with the fuel port 36 via a fuel passage 52, and the chambers 47 and 48 communicate with each other via a fixed orifice 53 opened in the metal diaphragm 44.

Here, a valve seat 54 is provided in the chamber 41 at a position corresponding to the orifice 53, and this valve seat 54 and the orifice of the metal diaphragm 44 constitute a distribution valve V2.

Further, each chamber 49 communicates with the chamber 48 of the distribution valve V2 via a fuel passage 55, and each chamber 50 communicates with the chamber 48 of the distribution valve V2 via a fuel passage 56, a fixed orifice 57 opened in the metal diaphragm 45, and a fuel passage 58. It communicates with pressure population 39.

Here, a fuel pipe 59 forming a valve seat is installed in each chamber 49, and a fuel pipe 59 and a fuel passage 6 are installed in each chamber 49.
0 to the fuel outlets 40a to 40d, respectively.

On the other hand, each chamber 50 communicates with the fuel return port 38 via a control hole 61 and a fuel passage 62.
2, a pressure fine adjustment device 66 consisting of an adjustment shaft 63, a return spring 64, and a leak-preventing O-ring 65 is attached to the nozzle 43 by screwing.
It is provided to adjust the opening area of the control hole 61.

In this way, the chamber 49, 50, the metal diaphragm 45, and the fuel vibro 0 constitute the isostatic valve V3, and the pressure fine adjustment device 66 constitutes a variable orifice that finely adjusts the fuel pressure applied to the homogeneous valve V3. .

The operation in the above configuration will be explained.

The amount of air taken into the engine 1 is arbitrarily controlled by opening and closing a throttle valve 4.

Intake air flows in from the air filter 2 and opens the sensing valve 6.
・Flows in the direction of the arrow.

The sensing valve 6 is balanced against the return spring 7 by the air drag force applied to the sensing valve 6 and the force by the pressure reactor 9 at a force equilibrium point.

Here, since the sensing valve 6 rotates together with the fuel metering shaft 8,
The fuel metering slit 21 has an opening area depending on the amount of intake air due to the fuel metering surface 23.

On the other hand, the fuel pumped from the fuel tank 30 by the fuel pump 31 is maintained at a predetermined pressure by the regulator 32 and flows into the lower chamber 26 from the conduit 34, which applies pressure to the metal diaphragm 19 and flows through the annular groove 24 for fuel regulation. Quantity 2
3, passes through the fuel metering slit 21, reaches the upper chamber 25, applies pressure to the metal diaphragm 19, flows out from the orifice formed by the metal diaphragm 19 and the fuel pipe 27, and is guided to the distributor 35.

At this time, the pressure difference between both sides of the metal diaphragm 19, that is, the front and rear of the fuel metering slit 21, is
The orifice formed by the tip of the fuel pipe 27 and the metal diaphragm 19 is maintained constant by adjusting the orifice formed by the tip of the fuel pipe 27 and the metal diaphragm 19 to maintain a set pressure difference determined by the stiffness of the fuel pipe 27 and the force of the spring 28.

Therefore, by controlling the area of the fuel metering slit 21, the amount of fuel for all cylinders is metered in accordance with the amount of intake air.

The fuel that enters the distributor 35 from the fuel inlet 36 is supplied from the fuel passage 52 to the fuel injection nozzle N through the distribution valve V2, the distribution valve V3, and the fuel passage 60 from each fuel outlet 40a to 40d. N is injected into the intake pipe (not shown) of the engine 10.

On the other hand, fuel led from the fuel supply source to the distributor 35 via the pressure port 39 flows into the chamber 51 through the fuel passage 58 and is distributed from this chamber 51 through each fixed orifice 57 and the fuel passage 56 to the chamber 51. flows into.

The fuel that has flowed into the chamber 50 flows through the control hole 61, the fuel passage 62,
It returns to the fuel tank 30 via the fuel return port 38 and regulator 37.

Here, the fuel pressure applied to the chamber 50 is roughly controlled to be approximately constant by the regulators 32, 3γ, and is further finely adjusted by the fixed orifice 51 and the pressure fine adjustment device to always maintain a constant pressure. .

In this way, since the fuel pressure in the chamber 50 is kept constant, the fuel pressure in the chamber 49 can be varied between the tip of the fuel pipe 59 and the metal diaphragm 45 by pushing down the metal diaphragm 45 until it becomes the same as the pressure in the chamber 50. An orifice is formed and a balanced state is reached.

Furthermore, since the chamber 49 communicates with the chamber 48, the pressure in the chamber 48 is ultimately the same as that in the chamber 50.

On the other hand, the pressure in each chamber 47 corresponding to each cylinder is
They are the same because they communicate with each other via 2.

Therefore, the amount of deflection of the metal diaphragm 44 is the same in each chamber 4γ, that is, the valve seat 54 and the metal diaphragm 44
The variable orifice formed by the fixed orifice 53 is the same, and the pressure difference across the orifice is the same, so the amount of fuel metered at the tip of the valve seat 54 is uniform in each cylinder.

However, due to unavoidable unevenness in processing accuracy, unevenness may occur in the amount of fuel in each cylinder.

In that case, by adjusting the pressure in chamber 48, the non-uniformity of the fuel quantity can be corrected.

Here, the pressure in the chamber 48 is adjusted as follows.

The fuel pressure in chamber 48 is thus the same as the fuel pressure in chamber 50.

Further, a fixed orifice 53 opens in the metal diaphragm 44, and the control hole 61 becomes a variable orifice at the tip of the adjustment shaft 63 by movement of the adjustment shaft 63, so that the fuel pressure in the chamber 50 varies slightly in each cylinder. be adjusted.

As a result, the fuel pressure in chamber 48 is finely adjusted and any uneven fuel pressure is corrected.

The adjustment shaft 63 is prevented from loosening by a return spring 64, and a leakage prevention O-ring 65 prevents fuel from leaking to the outside.

In this way, the fuel for all cylinders, which is metered by the fuel metering device according to the intake air amount, is evenly distributed by the distributor 35, and from each fuel injection nozzle N is accurately adjusted according to the intake air amount. fuel is supplied to each cylinder.

Although the above embodiment is for four cylinders, this type of distributor can be used depending on the number of cylinders.

In addition, although the sensing valve 6 detects the amount of intake air and measures the fuel in the explanation, it is of course possible to measure the fuel by detecting the intake negative pressure of the engine, the engine speed, and other engine conditions. It is.

As described above, according to the present invention, only one fuel metering slit is required for metering fuel according to the amount of intake air, which is easier than in the case where a fuel metering section is provided for each cylinder of the engine. It has the excellent effect of being able to be manufactured easily and supplying and distributing fuel with high accuracy according to the amount of intake air.

Further, the distributor has the advantage that it can be manufactured relatively easily and inexpensively using conventional processing techniques.

[Brief explanation of drawings]

1 and 2 are configuration diagrams showing one embodiment of the device of the present invention, FIG. 3 is a partially cutaway sectional view showing the distributor shown in FIG. 2, and FIG. - It is a longitudinal cross-sectional view along the A line. 1... Internal combustion engine, 16... Fuel metering device, 21... Fuel metering slit, 35...
...Distributor, 44°45°----Metal diaphragm, 47,48,49°50... Chamber, 52,6
0...Fuel passage, 53...Fixed orifice, 66...Pressure fine adjustment device, No...
・Fuel injection nozzle, Vl... Constant differential pressure valve, V2
...Distribution valve, v3...concave ring positive and negative.

Claims (1)

[Scope of Claims] 1. A fuel comprising one fuel metering slit whose area is controlled according to the intake air amount of the internal combustion engine, and a constant differential pressure valve that maintains a constant fuel pressure difference before and after the fuel metering slit. A fuel control device for an internal combustion engine that controls fuel supplied to a fuel injection nozzle by a metering device, comprising two chambers partitioned by a diaphragm, and a fixed orifice opened in the diaphragm so as to communicate these two chambers; A number of distribution valves equal to the number of cylinders of the internal combustion engine, each consisting of a valve seat provided at a position corresponding to the fixed orifice, and a fuel passage that guides fuel from the fuel metering device to one chamber of each of the distribution valves; the same number of equal pressure valves as the internal combustion engine, which communicate with the other chamber of the distribution valve and maintain the fuel pressure in the other chamber at a constant pressure;
and a distributor having a fuel passage for guiding fuel from the equal pressure valve to the fuel injection nozzle, and distributes the fuel from the fuel metering device according to the number of cylinders of the internal combustion engine. Engine fuel control device. 2. A chamber through which the equal pressure valve communicates with the other chamber of the distribution valve, a chamber partitioned from this chamber by a diaphragm to which a predetermined fuel pressure is applied, and a pressure fine adjustment device for finely adjusting the fuel pressure applied to this chamber. Claim 1 having
A fuel control device for an internal combustion engine according to paragraph 1.